EXPERIMENTAL MODEL INVESTIGATING POTENTIAL OF GEOTHERMAL .
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186936GSJ: Volume 7, Issue 3, March 2019, Online: ISSN AL MODEL INVESTIGATING POTENTIALOF GEOTHERMAL HEAT ENERGY IN RECYCLINGPOLYETHYLENE TEREPHTHALATE: CASESTUDY OF OLKARIAAnyona Moranga Kennedy1, Prof. Nicholas O. Mariita2, Dr. Benson Ongarora31. Department of Mechanical Engineering and Research, Kisii National Polytechnic,Kenya. Email: kanyona8@gmail.com, Phone: 07230774772. Director Geothermal Training & Research Institute Dedan Kimathi University of TechnologyKenya. Email: nicholas.mariita@dkut.ac.ke Phone: 07232978153. Department of Chemistry, Dedan Kimathi University of Technology, Kenya. Email:benson.ongarora@dkut.ac.ke, Phone: 0725897435ABSTRACTGeothermal energy is one of the clean, sustainable and renewable resources which provideheat energy that is derived from radioactive decay elements within the earth’s crust. The nonelectric utilization (direct use) of geothermal heat has been reported in various domains that havea need for sustainable supply of heat energy. Adoption and direct use of geothermal energy inKenya is one way which can enable waste control to enhance environmental protection andoptimize the use of energy. In this research, heat energy from the geothermal well was simulatedusing an experimental model in which polyethylene terephthalate (PET) pieces were melted andmoulded into usable products under suitable pressure conditions. The objective of this study wasto investigate the potential of using geothermal heat energy in recycling PET plastics through anexperimental model. The ground plastic waste material was exposed to heat and the resultingmolten medium was subjected to selected polymer processing techniques to obtain desiredproducts. The suitability of geothermal conditions in recycling PET was investigated throughnumerical analysis. In the design, the study performed experiments on three controlled factorsGSJ 2019www.globalscientificjournal.com
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186937temperature, velocity and pressure. The data collected was analyzed by use of MATLAB. Thisstudy established through experimental model that geothermal heat energy conditions in Olkariaare viable in recycling PET plastics. These findings, will enhance control of environmentalpollution and create job opportunities in the recycling process. The study recommends thatKenGen should explore the utilization of geothermal energy in the recycling of PET plastics.Key words: experimental model, geothermal heat energy, recycling and polyethyleneterephthalate1.0 IntroductionPlastics are carbon-based polymeric materials comprising of hulk organic molecules. Thesematerials can be designed in different shapes through assorted methods such as extrusion,moulding, artifact or gyrating (Arena et al, 2016). Modern plastics retain a quantity of awfullydesirable physiognomies; enough strength to mass proportion, superb thermal properties,electrical insulation, resistance to acids, alkalis and solvents. These polymers are made of a chainof repeating units identified as monomers (Achou, 2016). The construction and degree ofpolymerization of a given polymer govern its physiognomies (characteristics).There are six major plastic polymers that have found application in different spheres of life.These include polyethylene terephthalate, high flux of polyethylene, least density polyethylene,polypropylene and polystyrene. The most common applications for these materials include themanufacture of household items such as kitchen cutlery, car body parts, soft drink bottles,plumbing fittings, greenhouses and grocery store trays among other uses. This illustrates thewide range of application of the plastics in our daily lives. Among the highest worth end-uses forsecondhand PET plastic is the production of novel PET bottles and vessels. Though, renewedPET can be completed into many other goods (Abugri, 2012).According to United Nations Environmental Program (2018) report, it is projected that one to 5trillion PET plastics are consumed worldwide each year. Five trillion is virtually 10 millionplastic bags per minute. If tied together, all these plastic bags could be spread around the worldseven times every hour. Plastic containers accounts for close to half of all plastic discardedglobally, and much of it is thrown away within just a few minutes of its first use. Most plasticsare possibly single-used, but that does not depict that they are easily disposable as shown inGSJ 2019www.globalscientificjournal.com
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186938Figure 1.1. When discarded in landfills or in the environment, plastic can take up to a thousandyears to decompose.Figure 1.1: Global uses of PET packaging in million metric tonnes (Geyer, Jambeck, and Law,2017)According to Applied Market Information (AIM, 2018) report, Africa represents one of the leasttechnologically advanced continents. However, it’s one of the most stirring markets for polymersin the world today. It is an unlimited continent with a very hefty, growing and youthfulpopulation currently highly concentrated in urban areas. Development is not only engineered byits ordinary resources and minerals but also by its escalating consumer markets giving upswingto a growing demand for an extensive range of products using plastics from automotive tomobile phones, building and packaging industry. While much of this is still presently imported,there is now substantial investment going on in PET plastics processing set-ups motivatingdouble digit evolution in polymer plea.In Kenya, the use of PET plastics is a common practice, day in day out. It is worth noting that theestimated amount of plastic packaging from trade and manufacturing is approximately 270,000tonnes per year while the figure based on South Africa data is approximately 240,000 tonnes peryear (Elliott et al. 2018). Most of these plastics, after use are discarded to the environmentwillingly or unwillingly. Once they enter into the environment, plastics can stay for a prolongedperiod of time. According to Bashir (2013), plastic bags take over 1,000 years to photo-degrade.GSJ 2019www.globalscientificjournal.com
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186939The degradation process introduces poisonous (toxic) waste products into the environment.These products in turn pollute the vital pillars of various ecological niches. On the other hand,hundreds of these bags are inhaled or consumed by various animals at various levels in Kenya asshown in Figure 1.2Figure 1.2: Poor waste management in an urban set-up in Kisii County (Courtesy of research2017 Kisii County)Geothermal energy is a form of heat energy produced naturally and stored in the Earth. Thisenergy is obtained from the formation of the planet and from radioactive decay of materialswithin the crust. The formation of its reservoir depends on three parameters; source of heat,recharge (fluids) and the permeable zones as shown in Figure 1.3. These parameters aredetermined through the exploration process with the aid of geophysics, geology andgeochemistry information.GSJ 2019www.globalscientificjournal.com
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186940Figure 1.3: Illustration of the formation of a geothermal reservoir (Geothermal EnergyAssociation, 2014)Geothermal energy is endowed with a variable temperature gradient. This form of energy has abig influx of uses that result in multidimensional impact towards economic growth anddevelopment (Geothermal Energy Association, 2013). Kenya, as a developing country, has thisimportant resource along the Rift Valley. Proper utilization of this resource provides a stablechannel which can open more sources of income and job opportunities to its population.According to Kiruja (2011), geothermal resources are classified as low, medium or high enthalpydepending on the thermodynamic conditions of the reservoir. High enthalpy sources are used forproduction of electricity, while low and medium enthalpy sources are mainly for directapplications.2.0 Statement of the problemUse of plastics is a common phenomenon for all people in various aspects of life. Conferring tothe United Nations Environment Program (2015), the production of PET plastics globallyexceeded 311 million metric tonnes. Plastics Europe report (2016), indicates that the productionof plastics since 2013 has been on an upward trend. After use, most of these plastics end upbeing disposed through the wrong channels. This results in environmental pollution since they donot decompose; they photodegrade instead. The process of photo degradation takes a long periodof time and this escalates the effect of pollution. This prompted the study to design anGSJ 2019www.globalscientificjournal.com
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186941experimental model to investigate the possibility of using geothermal energy in the recycling ofPET plastics to reduce the side effects to the environment.2.1 Main objectiveTo establish a mathematical model to analyse the potential of using geothermal heat energy inOlkaria for recycling PET plastics through experimental approach.3.0 MethodologyThis study adopted an integrated methodology that involved the assessment of an experimentalmodel to investigate geothermal conditions through numerical analysis. The methodology wasclassified into six blocks (I-VI) with the activities carefully designed to establish the use ofexperimental and geothermal data to achieve stated objective. Using an experimental model to investigate the potential of using geothermal energy inrecycling PET plastics.Figure 1.4: Schematic representation of the integrated research methodologyFigure 1.4 depicts how the research conducted the study to gather geothermal data from Olkaria,engineering design and laboratory studies for recycling PET plastics. The research employed theengineering concepts in design, pure, applied and social science at given levels to meet the needsof objectives of the study. The levels used were: collection of data, mathematical modeling,analysis, design, construction, testing and optimization by using experimental approach toGSJ 2019www.globalscientificjournal.com
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186942investigate the potential of using geothermal energy in recycling PET plastic. The optimizationprocess involved various construction, laboratory evaluation and statistical analysis as show inFigure 1.5.Figure 1.5: Optimization stages for recycling PET plasticsThe Olkaria volcano complex is situated to the south of Lake Naivasha within the Great RiftValley of Kenya. It is geothermally dynamic area and is being used to produce clean electricpower. The area has an estimated potential of 2,000 MW. The geothermal fields and powerplants lie within the Hell's Gate National Park. The area is about 120 kilometres (75 miles) fromNairobi. It is to the south of Ol Doinyo Eburru multifaceted and north of the Suswa volcano; it iseast of the rift valley's western margin and west of Mount Longonot, a stratovolcano. Thevolcanic field covers 240 square kilometres (93 square miles). The geographical coordinates ofOlkariaGeothermalcomplexare0 53'27.0"S,36 17'21.0"E(Latitude:-0.8908;Longitude:36.2892). Major economic activities carried out in this area include; dairy farming,crop farming, nomadic pastoralism and geothermal power development. It is endowed withgeothermal prospects along the East African Rift Valley as shown in Figure 1.6.GSJ 2019www.globalscientificjournal.com
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186943Figure 1.6: Map showing Olkaria geothermal volcanic complex (KenGen, 2016)4.0 Results and DiscussionThe results of the study are presented below.The study obtained Olkaria Domes well reports which are displayed in Table 1.1. This data wascompared with experimental data using MATLAB to meet the objectives of the study.GSJ 2019www.globalscientificjournal.com
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186944Table 1.1: Olkaria well parameters derived from the official KenGen reportsWellnameTypeDepth TVD Measured Massflow Whp(vertical or (m)0BHT 907A Directional2870285105.35.2858.31801OW-911A 02OW-804A DirectionalN145EOW-802A DirectionalN137EOW-804MeanVerticalVerticalTable 4.1, shows the well depth, temperature conditions at bore head, mass flow, head pressure,steam velocity and enthalpy in which various conditions were obtained. The temperature,pressure and velocity conditions of this data was used for analysis. This was done in relation toexperimental findings using the mathematical model.GSJ 2019www.globalscientificjournal.com
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-91869454.1 Energy equationThe change in heat is governed by an equation that is very similar to the second Navier-Stokesequation seen earlier. The heat diffusion equation (Equation 4.1) that gives the change intemperature : 2 2 k 2 2 u t y x y x (4.1)This equation has two right-hand terms: the diffusion of heat and heat convection. The parameterk is called the thermal diffusion constant, and it takes on a small value for those materials that wesimulate. The research investigated both temperature of molten plastic in the flow channel. Forthe Hybrid scheme (HS), the values t yy xx x and y in Equation (4.2) were replaced bycentral difference approximation, the study found out that: ik 1, j 2 ik, j ik 1, j ik, j 1 2 ik, j ik, j 1 ik 1, j ik 1, j ik, j 1 ik, j 1 ik, j 1 ik, j u k 22 t2x2 y x y (4.2)The effect of Re on the fluid horizontal velocity was then investigated. Taking x y 0.25and t 0.01 ,k 0.196 and u 100, the scheme was obtained.3.775 ik 1, j 4.1 ik, j 1.225 ik 1, j 1.225 ik, j 1 2.775 ik, j 11(4.3)Taking i 1, 2, 3 .10 and k 0, j 1 the study found out the following systems of linearalgebraic equations:GSJ 2019www.globalscientificjournal.com
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186946111003.775 2,1 4.1 1,1 1.225 0,1 1.225 1,0 2.775 1,2111003.775 3,1 4.1 2,1 1.225 1,1 1.225 2,0 2.775 2,2111003.775 4,1 4.1 3,1 1.225 2,1 1.225 3,0 2.775 3,21003.775 5,1 4.1 4,1 1.225 3,1 1.225 4,0 2.775 4,2111003.775 6,1 4.1 5,1 1.225 4,1 1.225 5,0 2.775 5,2111003.775 7,1 4.1 6,1 1.225 5,1 1.225 6,0 2.775 6,2(4.4)111003.775 8,1 4.1 7,1 1.225 6,1 1.225 7,0 2.775 7,21110 4.1 8,1 1.225 7,1 1.225 80,0 2.775 8,23.775 9,1111003.775 10,1 4.1 9,1 1.225 8,1 1.225 9,0 2.775 9,2111003.775 11,1 4.1 10,1 1.225 9,1 1.225 10,0 2.775 10,2When θ (x, 0) θ (x, 2) 180 C, gave the matrix-vector Equation 4.11 below. 11 2.718 3.77500000000 4.1 21 1.225 4.1 3.7750000000 7.389 0 1.225 4.13.775000000 31 20.08 0 1.225 4.13.77500000 41 54.59 0 000 1.225 4.13.7750000 51 148.41 000 1.225 4.13.775000 61 403.43 0 00000 1.225 4.13.77500 1096.63 71 2980.95 00000 1.225 4.13.7750 0 81 000000 1.225 4.1 3.775 22026.47 0 0000000 1.225 4.1 91 43076.43 0 101 4.2 Experimental resultsThe study performed the experimental processes as shown in Figure 1.7Figure 1.7: Experimental processes in recycling of PETGSJ 2019www.globalscientificjournal.com(4.5)
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186947In the collection unit, wastes of PET plastics were collected from dust bins. In this unit, cleaningwas done using warm water at 80 0C to remove any grease and labels as shown in Figure 1.7 (a).After cutting the plastics, the samples were placed inside the autoclave. The drying was doneusing heat from the sun as shown in Figure 1.7 (b). The study took a sample of 0.5 kg of PETwhich was weighed using a beam balance; the sample was placed inside a clean pan which wasin turn placed in the grid basket of the autoclave. The autoclave was set at the required operatingconditions and closed for melting process as shown in Figure 1.7 (c). It was thereafter placedinside the fume chamber to control pollution to the surroundings. It was at this stage thatexperimental data were taken. After melting, the sample was removed under controlledconditions and poured into a container with the given dimensions under pressure to produce therequired products for various uses as shown in part (d) and (e) of Figure 1.7. The studyconducted experiments at various temperatures between 140 0C to 220 0C using a sample of 0.5kg of PET with the aid of an autoclave at a pressure of 1 bar and yielded the results shown inTable 1.2.Table 1.2: Experimental results obtained using an autoclaveHeatingtemp.(0C)Time for melting 4.4622099.11SDVelocity of moltenlong channel at 1 m(m/s)TrialTrial TrialMean(m/s)SD123 0.040.1250.1230.1250.124 0.001120.42 0.030.1530.1510.1520.152 0.001110.40110.43 0.030.1800.1770.1800.179 0.002104.48104.50104.48 0.020.2140.2170.2140.215 0.00299.1399.1599.13 0.020.2330.2330.2360.234 0.002Table 1.2 indicates that the study investigated the time for melting PET and the velocity of themolten material at specific temperatures under constant pressure. In each heating temperature,three trials were conducted of which their respective means and standard deviation are shown inGSJ 2019www.globalscientificjournal.com
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186948the table. The time taken for PET to melt in each of the trials was recorded immediately whensteam was released from the valve which was connected to the fume chamber. At the chamber,observations were made on the changes in the universal indicator once it was in contact withfumes from melting PET plastics. Further, the study analysed the melting temperature againsttime take and obtained the results depicted in Figure 1.8.Figure 1.8: Experimental melting temperature against timeFrom Figure 1.8, the study noted that the melting temperature and time displayed an inverselyproportional trend. Along the graph, at 180 0C a distinctive change was noted. This temperaturedepicts the most optimal melting temperature of PET under required conditions. According toWong (2010), PET consists of polymerized units of the monomer ethylene terephthalate, whichis frequently recycled at optimal temperature of 180 0C.The research also established that geothermal and experimental temperature along the channel offlow have a positive linear correlation (Figure 1.9). This depicts that geothermal has gotsufficient temperature conditions for recycling PET plastics. Rop (2012), established that Olkariawell domes field is a high temperature zone ranging from 200 0C to 360 0C at -500 m above sealevel.GSJ 2019www.globalscientificjournal.com
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186949Figure 1.9: Geothermal and experimental temperature from Table 1.1 and 1.2 respectivelyagainst length of molten plastic flow channel.In addition, the study investigated geothermal enthalpy using the data shown in Table 1.1through analysis along the flow channel and obtained a summary shown in Figure 1.10.Figure 1.10: Geothermal enthalpy against length of molten plastic flow channelGSJ 2019www.globalscientificjournal.com
GSJ: Volume 7, Issue 3, March 2019ISSN 2320-9186950From Figure 1.10, the study revealed that geothermal wells have varying enthalpies dependingon location. The graph depicts that the enthalpy along the channel of
model to investigate geothermal conditions through numerical analysis. The methodology was classified into six blocks (I-VI) with the activities carefully designed to establish the use of experimental and geothermal data to achieve stated objective. Using an experimental model to investigate the potential of using geothermal energy in
Keywords: Power analysis, minimum detectable effect size, multilevel experimental, quasi-experimental designs Experimental and quasi-experimental designs are widely applied to evaluate the effects of policy and programs. It is important that such studies be designed to have adequate statistical power to detect meaningful size impacts, if they .
Experimental and quasi - experimental desi gns for generalized causal inference: Wadsworth Cengage learning. Chapter 1 & 14 Campbell, D. T., & Stanley, J. C. (1966). Experimental and quasi -experimental designs for research. Boston: Hougton mifflin Company. Chapter 5. 3 & 4 Experimental Design Basics READINGS
Quasi experimental designs are similar to true experimental designs but in quasi experiments, the experimenter lacks the degree of control over the conditions that is possible in a true experiment Some research studies may necessitate the use of quasi designs rather than true experimental designs Faulty experimental design on the .
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Chapter 3: Research design and methods for investigating the factors affecting teachers’ use of ICT (Phase 1) Page 63 Chapter 3 Research design and methods for investigating the factors affecting teachers’ use of ICT (Phase 1) The first section of this chapter deals with general design issues for the study as a whole.
Lesson Title: Investigating Special Quadrilaterals Lesson duration: 60-80 minutes Stage: 2 Year: 3 Rationale: By investigating the properties of special quadrilaterals, children build a deep understanding of what they are, and learn to identify and describe them when presented in different sizes and orientations. To ensure students d
Jeffery was a good introduction to scoping. In appropriate order different bureaucratic levels were tackled, always sensitive to the pressures in each place. The many discussions with Roger proved useful during the field work later. For example, we confronted the problem of finding very large sample sites which were suitable on other parameters. So we discussed how this should be tackled .
